Abstract: PO6.00004 : On the role of an inverse cascade in ion-scale turbulence

Authors:

Gabriel Plunk(University of Maryland, College Park)

Tomo Tatsuno(University of Maryland, College Park)

Bill Dorland(University of Maryland, College Park)

Theoretical works using simplified models of magnetized plasma
turbulence have brought a deeper understanding of mechanisms for
zonal flow generation and saturation of ion-scale turbulence, and
inverse cascade in particular is sometimes cited as an important
player. However, these works investigate the Hasegawa--Mima (HM)
equation or the Generalized Hasegawa--Mima (GHM) equation that
assume cold ions and are thus not applicable for most plasmas.
In this work we find a rigorously derived two-dimensional fluid
system, valid at finite ion temperature, for turbulence at
wavelengths larger than the ion Larmor radius. It is shown that
the theoretical basis for an inverse cascade within this model is
not present. We also perform the modulational/secondary
instability analysis to investigate other mechanisms that are
believed to be linked to the growth of a large-scale zonal
component. Finally, the results are investigated by direct
numerical simulation with AstroGK.

To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2009.DPP.PO6.4